Merge pull request #6 from denistribouillois/SlicingPlaneAnyDirection

Slicing Plane in any direction

Assets/Scripts/VolumeObject/SlicingPlaneAnyDirection.cs

@@ -0,0 +1,14 @@
+using UnityEngine;
+
+[ExecuteInEditMode]
+public class SlicingPlaneAnyDirection : MonoBehaviour
+{
+    public Material mat;
+    public Transform volumeTransform;
+
+    void Update()
+    {
+        mat.SetVector("_PlanePos", volumeTransform.position - transform.position);
+        mat.SetVector("_PlaneNormal", transform.forward);
+    }
+}

Assets/Scripts/VolumeObject/SlicingPlaneAnyDirection.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 030645f63ce11d14ea77ce39291d70da
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Shaders/DirectVolumeRenderingShader.shader

@@ -48,6 +48,9 @@
             float _MinVal;
             float _MaxVal;
 
+            float3 _PlanePos;
+            float3 _PlaneNormal;
+
             // Gets the colour from a 1D Transfer Function (x = density)
             float4 getTF1DColour(float density)
             {
@@ -116,6 +119,18 @@
                     if (density < _MinVal || density > _MaxVal)
                         src.a = 0.0f;
 
+                    // Move the reference in the middle of the mesh, like the pivot
+                    float3 pivotPos = currPos - float3(0.5f, 0.5f, 0.5f);
+
+                    // Convert to world position
+                    float3 pos = mul(unity_ObjectToWorld, -pivotPos);
+
+                    // If the dot product is < 0, the current position is "below" the plane, if it's > 0 it's "above"
+                    // Then cull if the current position is below
+                    float cull = dot(_PlaneNormal, pos - _PlanePos);
+                    if (cull < 0)
+                    	src.a = 0;
+
                     col.rgb = src.a * src.rgb + (1.0f - src.a)*col.rgb;
                     col.a = src.a + (1.0f - src.a)*col.a;